Electrical connections between components of electrical systems are generally facilitated by numerous conductors that carry electrical current. For example, a copper wire may carry current from a source of electrical power to a device that requires power. A conductor may be insulated to prevent current from leaving the conductor. Under certain circumstances, such as upon the occurrence of an overcurrent condition, an electrical conductor may heat up excessively and cause the insulation surrounding the conductor to melt, thereby exposing the conductor. Upon such exposure, current may be allowed to leave the conductor and travel through the air to a nearby conductive body. This unintended current flowing from the conductor to the nearby conductive body may result in an “electrical arc” or “arc-flash.” These arc-flash conditions can cause significant damage to nearby equipment and may cause injury to nearby personnel. The detrimental effects of electrical arcing can be particularly severe in electric power transmission and distribution systems.
Devices are currently available that are capable of detecting arc-flash events and arresting electrical currents in electrical conductors in response to a detected event. For example, arc-flash relays are microprocessor-based devices that employ optical sensors disposed in the vicinity of electrical connection points to detect the onset of an arc-flash. Upon the occurrence of a flash, the arc-flash relay transmits an electrical pulse that trips a circuit breaker supplying the affected system components. The total arcing time is thereby effectively reduced to the mechanical opening time of the circuit breaker. This is a significantly faster response than can be provided by traditional current-measuring relays. There is therefore less damage to electrical equipment and fewer and less severe injuries to personnel.
While arc-flash relays are effective for arresting electrical current and mitigating damage and injury that may result from an arc-flash condition after an arc-flash has already occurred, they are not capable of preventing arc-flashes from occurring in the first place.